KSI-L007-000

1

S3843P

Current Mode PWM Controller

Descriptions

The S3843 is fixed Current PWM controller for Off-line and DC-DC converter applications.

The internal circuits feature a trimmed oscillator for precise duty cycle control, a

temperature compensated reference, high gain error amplifier current sensing comparator,

and a high current totempole output for driving a power MOSFET. Protection circuitly

includes built in under voltage lockout and current limiting. S3843 have UVLO threshold of

8.4V(on) and 7.6V(off). S3843 can operate within 100% duty cycle.

Features

• Optimized for off-line and DC to DC converters

• Low start up current < 1 mA

• Operating range up to 500 KHz

• Pulse-by-pulse current limiting

• Under Voltage Lock Out with hysteresis

•

High current totempole output

• Short shutdown delay time ; typical 100nsec

Ordering Information

Type NO.

Marking

Package Code

S3843P

S3843P

DIP-8

Outline Dimensions

S

PIN Connections

1. Output / Compensation

2. Voltage feedback. Input

3. Current sense Input

4. Rt/Ct

5. GND

6. Output

7. Vcc

8. Vref